There is no sound in the Opera.

Hi.
I do not have sound in the Opera browser (45.0). The indication at the top of the tab is, but sound is not transmitted to the system. In Pulse-audio does not appear even as a program reproducing sound.
System:
Processor 4x AMD A4-5000 APU with Radeon(TM) HD Graphics
Memory 1743MB
Operating System Ubuntu 14.04.5 LTS
Audio Adapter HDA-Intel - HD-Audio Generic
Sound works in all programs except Opera.
How to fix this problem?
Thank you for attention.